Let’s start at the very beginning, a very good place to start. Although if we were honestly going to start at the beginning, we’d need to start with the menstrual cups patented in the 1930s. Here’s a patent for a menstrual cup from 1932!

But for our purposes, and for me personally, the beginning of the modern, commercially viable menstrual cup is The Keeper, which was first manufactured in the US in 1987.

A Keeper menstrual cup stylishly presented on a piece of wood, maybe? Note the length of the uncut stem.

This is the only cup that was available for me to buy (in 2002, in Vancouver, British Columbia, Canada) when I wanted to find a safe, cheaper, less wasteful option for dealing with menstrual fluid. The Keeper is still available from their website (from whence I have also borrowed the above photo, since I no longer have my own to take a picture of). It came in 2 sizes, and I bought the smaller of the two, as this was what was recommended for menstruators who had never given birth vaginally, which was true of me then.

I used my Keeper for every period I had between the summer of 2002 and fall of 2004, and then used it part-time from 2004 to 2008, when I conceived my kid and stopped menstruating for a while. When my periods returned in 2010, I decided that the “gum rubber” of the cup had degraded too much to use it any longer and discarded it.

1. Material Quality – 4/10

The Keeper has always been described as being made of “natural gum rubber”, though I note the current addition of the parenthetical “(latex)” at the end of that description. The Keeper has also always been touted as having a usable life of up to 10 years.

As regards material strength and rigidity, the gum rubber used in the Keeper is not a bad choice. When using any menstrual cup that shares some slight variation of the bell-shaped cup with the Keeper, you generally insert it folded in one of several ways, and it’s important for the material that a cup is made of to have enough strength to consistently and without drama unfold again inside of the vagina.

Two more views of the Keeper. In the foreground, a side view showing the somewhat steeply conical bell shape of the cup, and the long untrimmed stem. You can just see one of the tiny air holes under the ridge below the rim, on the right-hand side. In the background is an image of a hand holding a Keeper that has been folded for insertion. It is shown end-on, perhaps to reassure the viewer that when folded, it isn’t too different in size to a standard tampon applicator.

Basically, the material of the cup needs to be able to resist the pressure of the vaginal walls enough to pop back into a cup shape, because it can’t catch menstrual fluid if it doesn’t. The gum rubber in the Keeper is sufficiently flexible to allow it to be easily folded without damaging the material, and sufficiently firm to be pretty reliable at popping back to its intended in-use shape. Almost as important, it also has enough rigidity to prevent the worst possible disaster of menstrual cup use: the dreaded “accidentally pushing it out of your vagina into the toilet while bearing down to poop” event. This can happen more easily if the material combined with the design of a menstrual cup allows too much horizontal (side-to-side) flex. This tragic event never once happened to me when using the Keeper.

But let’s get right to the critical point, here: gum rubber, natural or not, is simply not the best material for something you’re using this intimately and for this long. A menstrual cup is a device that you wear inside your body 24 hours per day for up to a week at a time. Ideally, you would want that device to be non-reactive, non-porous, and sterilizable in case of disasters as described above. Gum rubber is porous, so it is reactive and changeable in a way that medical grade silicone (the material used for almost all modern cups) simply isn’t. The gum rubber reacts to your vagina and its chemistry over time and can get darker or discolour. The Keeper website suggests that, “this natural discoloration is a sign that you are giving your cup a long and happy life. A discolored cup is still clean and very usable.” Perhaps so, but it can still be a little offputting to use a darkly mottled cup, and discolouration inevitably makes it harder to determine cleanliness through visual inspection. Is it darker under the rim because it’s discoloured or because there’s still residue that should be cleaned off? That’s not a pleasant judgment call to have to make.

Relatedly, In my experience and from conversations with friends, it seems that it’s not unusual to find that the Keeper develops a mild odour with use that seems impossible to completely remove by cleaning in the ways recommended by the manufacturer. Because boiling to sterilize the cup is not recommended – it harms the material and shortens its life – if a smell does develop, and you can’t shift it with soap or a mild vinegar solution, so long as it doesn’t become strong or quite unpleasant, you might just have to make the choice to live with it.

2. Design – 4/10

a. General Shape – 9/10

The Keeper has a very standard general design for a menstrual cup, a bell-shaped cup with a thicker band of material around the rim, “air holes” to release suction beneath that rim, and a long stem at the bottom. Most menstrual cups on the market shares these basic qualities, so the design differences come in the subtler details.

The general shape of the cup is fine. It has a somewhat steeper conical bell shape than some cups, but it’s hard to tell what practical difference this kind of variation makes. Certainly, the cup ably contains menstrual fluid in useful quantities.

The rim is a reasonably comfortable shape to insert when folded. The rounded rim and the thicker section of the cup below it, combined with the qualities of the material itself is likely what contributes to the Keeper’s reliability in unfolding once inserted. Basically, enough material has been included in the design to ensure the right degree of material strength.

The Keeper’s stem is comically long prior to first use, and the intention is that the Keeper’s user will trim the stem with scissors to the correct length for their anatomy. Users are supposed to leave the stem long enough so that it can be grasped in order to remove the cup, but short enough for the stem not to cause discomfort regardless of its wearer’s movements when the cup is positioned correctly. Ideally, the users shouldn’t be able to feel the stem at all when the cup is properly inserted. With the Keeper, I prefered a very short stem. Anything longer than around a quarter of an inch meant that I could feel the stem in my vaginal opening, and the sensation of this was unpleasant and sometimes sharply painful. Early experimentation helped me find the right length and I have found that slightly “beveling” the cut stem end with the scissors so that there were no sharp corners also helped. If I have one criticism of the stem, it is that because it was smooth and untextured, it was difficult to grasp, especially when wet or slippery from menstrual or vaginal fluid, which it usually is.

b. Surface Details – 0/10

Full disclosure: I HATE surface details on a menstrual cup. A menstrual cup is a practical object, spends its in-use time primarily invisible inside the body of its user, and very specifically is inside that body to collect menstrual fluid from the beginning to the end of its user’s period. Decorations are inappropriate, unnecessary, and usually counter-productive. Menstrual fluid is a substance that is perfectly natural and normal, but also sometimes, a bit… messy? Sometimes there are clots, or long gelatinous goo strings, and for some menstruators, menstrual fluid at the start and/or end of a period can be scant, thick, sticky, and brown/grey. Details imposed on the surface of the interior of the cup therefore primarily serve as anchor points for the messier parts of your menstrual fluid.

Note the interior surface details: raised measurement lines and “KEEPER” in all capitals stamped just inside the rim. These details make the Keeper harder to clean.

The Keeper has a plethora of surface details, including measurement markings within the cup and the word “KEEPER” in stamped on the interior of the rim. Measuring the volume of your menstrual fluid is an interesting novelty*, but I’m unconvinced that it’s a benefit that justifies that added time spent cleaning the gunge off these measurement lines with your fingernail. Also, the best way to make me hate and resent the name of your product is to design your product so that I have to spend time scraping sticky brown late-period menstrual fluid off your product name every. fucking. month. No love. This didn’t need to happen.

c. Air Holes – 0/10

Air holes are such a problem. It’s hard to know how important it is to have them in the first place. A few modern menstrual cups are designed without any air holes at all, and still seem perfectly usable. Nonetheless, air holes are pretty ubiquitous. Those in the Keeper are tiny. It seems as though the designer must have been concerned about the air holes permitting menstrual fluid leakage, as the air holes are just pin holes really.

Because the holes are so small and narrow they rapidly become clogged, and they’re too small to properly clean with any kind of tool you’re likely to have in your house. It’s also difficult to tell if they’re actually blocked, because they’re small and weirdly angled so it’s very difficult to get water to visibly flow through them even when they’re not clogged. Since the “natural gum rubber” is opaque, you can’t even tell by looking closely. It seems inevitable that a Keeper’s air holes probably function mainly as repositories for bacteria, which is a pretty unpleasant thought.

3. Ease of Use and Comfort (8/10)

The Keeper was my first cup, so it’s the one that taught me about cups. In using a cup there are a number of important considerations for ease of use. A few obvious considerations are if it is difficult to insert or remove, if it causes pain or discomfort, and whether or not the cup commonly leaks during standard usage. But perhaps most importantly to me is whether it is possible to unambiguously assess whether the cup has been inserted properly before you leave the bathroom. A cup that leaves this ambiguous is a cup that is introducing unnecessary stress into your life.

The Keeper, for the most part, was solid on this point. To insert it, I would generally sit on the toilet with legs spread, fold the Keeper into a tight “U” shape as shown in the image, wet it with water from the tap for minor lubrication, and pushed it into my vagina with my thumb and two fingers. Once inside, it usually only took a little bit of gentle nudging and repositioning to get it to sort of “pop” open inside, and this was accompanied by a very noticeable physical sensation. When I felt that sensation, I could then turn the cup with my fingers and it would rotate easily and smoothly inside my vagina, which confirmed that it was inserted properly and ready to go.

This insertion technique was relatively easy to learn and not painful. The tricky part was figuring out how to hold the Keeper once it was folded so that it didn’t pop open prematurely, and figuring out the right angle and pressure for comfortable insertion.

I did experience occasional leaks on heavy days, which is why I always work cloth pads on those days as a back-up. Leaks were more likely if I was sneezing or coughing frequently, while I was lying down for a long sleep overnight on a heavy day, or if I had to wait too long between emptying the cup on a heavy day. Occasionally it seemed as if the presence of a stool in my anus may have disrupted the Keeper’s position in my vagina and caused a leak. Completely leak-free periods were, for me, in the minority with the Keeper, perhaps only one in four, but the leaks were rarely catastrophic with the cloth pads as backups.

The Keeper was incredibly comfortable. Once I’d sorted out the stem length and figured out how to tell when the cup was properly inserted, I would usually not feel it at all when wearing it, except occasionally when laughing, coughing, or sneezing.

Conclusion

The Keeper was a great product in its time, and for over a decade, pretty much the only product of its kind available. But I truly believe its time has passed, mainly because of the problems inherent in the “natural gum rubber” still being used to make it. If it was somehow once again the only menstrual cup available in the world and I needed to get a cup, I would buy it again in a heartbeat, because it did work for me for a long time despite its problems, and it has worked for many other menstruating folks as well. But given almost any other option, and especially given the many excellent options available today, I cannot recommend it except as a museum piece. Sorry, Keeper.

*It’s important to note that the volume of your menstrual fluid is not the volume of your blood loss as a result of menstruating. Around half of this fluid is made up of other fluids, expelled uterine lining, etc.